1. Field of the Invention
The present invention relates to an inspection device of a plugged honeycomb structure and an inspection method of the plugged honeycomb structure. More particularly, it relates to an inspection device of a plugged honeycomb structure which can efficiently and simultaneously inspect the depths and defects of plugged portions, and an inspection method of the plugged honeycomb structure.
2. Description of the Related Art
In various fields of chemistry, electric power, iron and steel and the like, a ceramic honeycomb structure which is excellent in heat resistance and corrosion resistance is employed as a carrier for a catalyst device and a filter used for an environmental countermeasure, the collection of a specific material or the like. The honeycomb structure is a cylindrical structure having partition walls which partition a plurality of cells extending from one end face to the other end face of the structure. Especially in recent years, a plugged honeycomb structure has been developed by alternately plugging open frontal areas of cells in both end faces of the honeycomb structure, and has frequently been used as a diesel particulate filter (DPF) which collects a particulate matter (PM) discharged from a diesel engine or the like.
In such a plugged honeycomb structure, plugged portions uniformly have a predetermined constant depth. This is because if the depths of the plugged portions are small dimensions, the plugged portions easily break down. If the depths of the plugged portions are large, a pressure loss increases, and a filter area of the structure as the filter decreases. To solve such a problem, a method for measuring the depths of the plugged portions of the plugged honeycomb structure is suggested (e.g., see JP-A-2008-58116).